Ultrashort laser pulses for precision laser surgery

The surgical treatment of early stage colorectal cancer is typically based on diathermy and electrocautery tools. They imply restraints on precision and the risk of collateral thermal damage to the healthy tissue. We present the resection of intestine by means of picosecond laser pulses as a potential alternative to mitigate these limitations. High intensity ultrashort laser pulses enable nonlinear absorption processes, plasma generation, and as a consequence a predominantly non-thermal ablation regime.

Robust process parameters for the laser resection are demonstrated using fresh in-vivo pig intestine samples. Square and circular cavities with comparable thickness to early stage colorectal cancers are removed for a wavelength of 1030 nm and 515 nm using a picosecond laser system. The corresponding histology sections exhibit in both cases only minimal collateral damage to the surrounding tissue. The resection depth can be controlled precisely by means of the pulse energy. Furthermore, by adjusting the overlap between successive laser pulses, it is possible to change to a regime of controlled heat transfer to the immediately adjacent tissue, in order to provide selective thermal damage. This can be beneficial for on demand haemostasis and laser coagulation.

Overall, the application of ultrafast lasers for the resection of intestine enables significantly improved precision and reduced thermal damage to the surrounding tissue compared to conventional techniques.